[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 280232
TCDAT1
TROPICAL STORM FRANKLIN DISCUSSION NUMBER  27
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT WED JUL 27 2005

WHILE FRANKLIN CONTINUES TO GENERATE COLD CONVECTIVE TOPS...COLDER
THAN -70C...A 0055Z SSM/I OVERPASS INDICATES THAT NO WRAPPING OF
THE CONVECTION HAS OCCURRED SINCE THIS AFTERNOON.  INDEED...THE THE
MICROWAVE DATA SHOWS THE CENTER IS AGAIN EXPOSED TO THE NORTH OF
THE MAIN CONVECTION...ALTHOUGH UNDER THE CIRRUS OUTFLOW.  WHILE THE
REASON FOR THIS IS NOT CLEAR...IT SUGGESTS THAT FRANKLIN IS NO
STRONGER THAN IT WAS 6 HR AGO.  THE INITIAL INTENSITY REMAINS 45 KT
IN AGREEMENT WITH SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB.

THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 360/5...WITH THE
MICROWAVE DATA SUGGESTING FRANKLING MIGHT BE MOVING A LITTLE
FASTER.  THE TRACK FORECAST IS STRAIGHTFORWARD.  FRANKLIN IS
BETWEEN A BUILDING DEEP-LAYER RIDGE OVER THE NORTH CENTRAL ATLANTIC
AND A MID/YUPPER-LEVEL TROUGH AND ASSOCIATED COLD FRONT OVER THE
NORTHEASTERN UNITED STATES.  THIS COMBINATION SHOULD GRADUALLY TURN
FRANKLIN NORTHEASTWARD IN THE NEXT 12-24 HR...WITH GRADUAL
ACCELERATION TOWARD THE NORTHEAST THEREAFTER.  ALL TRACK GUIDANCE
AGREES WITH THIS SCENARIO...AND THE OFFICIAL FORECAST IS SIMILAR
TO...BUT SLIGHTLY LEFT OF...THE PREVIOUS TRACK.

VERTICAL SHEAR IS DECREASING OVER FRANKLIN AS THE UPPER-LEVEL FLOW
BECOMES GENERALLY SOUTHERLY OVER THE STORM.  THIS ALLOWS A WINDOW
OF OPPORTUNITY FOR FRANKLIN TO STRENGTHEN BEFORE THE APPROACHING
TROUGH INCREASES THE SHEAR...AND THE STORM MOVES NORTH OF THE GULF
STREAM.  BOTH OF THESE SHOULD OCCUR IN 24-36 HR.  THE INTENSITY
FORECAST CALLS FOR STRENGTHENING TO 55 KT IN 24 HR...FOLLOWED BY
WEAKENING AS FRANKLIN MERGES WITH THE COLD FRONT AND BECOMES
EXTRATROPICAL.  IT SHOULD BE NOTED THAT 55 KT IS HIGHER THAN EITHER
THE SHIPS OR THE GFDL MODELS ARE FORECASTING.  AFTER EXTRATROPICAL
TRANSITION...FRANKLIN WILL LIKELY BE ABSORBED BY THE FRONT IN 72-96
HR.

FORECASTER BEVEN


FORECAST POSITIONS AND MAX WINDS

INITIAL      28/0300Z 34.3N  69.4W    45 KT
 12HR VT     28/1200Z 35.5N  69.0W    50 KT
 24HR VT     29/0000Z 37.3N  67.1W    55 KT
 36HR VT     29/1200Z 39.3N  64.4W    55 KT
 48HR VT     30/0000Z 41.8N  60.3W    45 KT...BECOMING EXTRATROPICAL
 72HR VT     31/0000Z 46.0N  51.0W    30 KT...EXTRATROPICAL
 96HR VT     01/0000Z...ABSORBED BY FRONTAL SYSTEM


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